Generally, in times of an increasing number of wireless communication applications employing MIMO (Multiple Input Multiple Output) systems such as LTE (Long Term Evolution), there is a growing need of a testing device and a testing method for testing devices under test applying such systems.
U.S. Pat. No. 7,480,328 B2 discloses a signal generator for generating a digitally modulated radio-frequency signal, the signal generator having a fading unit but only a single RF (radio frequency) output. As this signal generator has just one RF output it is therefore not suitable as a testing device for testing devices under test having multiple inputs, or multiple outputs respectively. Furthermore, due to the single RF output, testing a device under test with respect to fading based on multiple signal paths between transmitter and receiver is also not possible. However, investigating the phenomenon of fading typically occurring at wireless communications is very important because of its great impact on signal quality.
Accordingly, there is a need to provide a testing device and testing method for testing devices under test having multiple inputs, respectively multiple outputs, and for investigating the phenomenon of fading.